In the processing of liquids through devices such as filters, it is well known that gases are formed within the fluid often within the filter itself. These gases are either gases which had been entrained or dissolved within the fluid and which have now come out as bubbles within the liquid or are introduced into the fluid during processing.
These gases need to be removed in order to have efficient filtration. Gas tends to block portions of the filter surface making them unusable for filtration. When enough gas is formed on the filter surface, the filtration process essentially stops.
Additionally, many manufacturers of these liquids prefer or require that no gas be contained or visible within their finished product. Therefore it is important if not imperative to remove the gas.
Typically, vents are formed on the upstream side of the filter housing so as to allow for the removal of gas from the liquid. The venting must be done in a manner that maintains a sanitary seal between the vent opening and the outside environment when the vent is closed.
These vents are sealed with a push/pull valve design as shown in prior art FIG. 1. A vent stop 10 is mounted within the opening 12 of the vent 14. The stop selectively opens and closes the vent 14 via a series of O-rings 16A and 16B. The vent 14 is opened by pulling the stop 10 outward until a passageway 18A is established with the passageway 18B of the vent opening 12. Gas that is at a higher pressure within the filter housing than the outside atmosphere flows from the inside of the housing to the outside of the housing via the passageways 18A and 18B. The vent 14 is closed by pushing the vent stop 10 back into the vent opening 12 so the passageway 18A is against the inclined portions 20 of the vent opening 12 which prevent any fluid (liquid or gas) from exiting the vent 14.
Such vents are required on many filters because venting must be done on a periodic basis to prevent gases from building up inside the filter such that performance is compromised. Typically, gas build up diminishes the efficiency of filters and the vents must be periodically opened to vent the accumulated gases.
To determine if accumulated gases are affecting performance, one may monitor the pressure drop of the filter (increases by a set % require venting) or throughput (decreases in a set % require venting). One may also dispense with such monitoring and merely schedule periodic filter venting.
A problem with prior art vent designs is that the vents need to be small, but are not ergonomically designed. They have an outer knurled surface designed to be manipulated in a cam fashion that is bruises the hands. Also, the cam action required coupled with the strong hand action needed to actuate the cam can result in de-coupling the vent stop from the vent housing or stripping the cam from the housing.
Another issue is that the prior art design does not allow one to open the vent sufficiently so as to allow the gas to escape in a reasonable amount of time. But, one does not want to open the prior art vent so quickly that the sanitary seal is compromised, such as actually pulling the stop off the vent or more commonly, fluid leaks out of the vent and along the outside of the vent where it is lost (on prior art vents that have only a single o-ring).
What is needed is a new sanitary seal and vent design using that seal which overcomes these problems. The present invention provides such a solution.